Process for treatment of gases arising from the heating of sulphide ores and the like



Dec. 15, 1931. KLENCKE 1,836,176 PROCESS FOR TREATMENT OF GASES ARISING FROM THE HEATING OF SULPHIDE ORES AND THE LIKE:

Filed Dec. 31. 1929 f/ecif/ba/ PrecfhE/b/t l N I "EN TOR.

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0! IlOSANGELES, GALIFORNIA, A CORPORATIOI I Application filed December 81, 1989, Serial No. 417,780, and in Belgium January 88, 1989.

This invention relates to the electrical precipitation of-dust or suspended matter from t e gases arising from the sintering, roasting, volatilization or other heat treatment of ores and the like, and particularly from heating apparatus of the travelin charge type.

he apparatus known as the Wight-Lloyd straight line machine is an. example of an apparatus of this type .commonly used in the sintering, roasting or other heat treatment of ores and the like, and the descriptionherein will be directed particularly to the carrying out of my invention in such an apparatus, although 1t will be understood that any other apparatus of the same general ty e may be used.

In the o ration of apparatus ofthis type, a relative y thin layer orcharge of ore or other material to be treated is caused to travel in a straight line path. At a point near the beginning of its travel the charge is ignited in any sultable manner and in the subsequent part of its travel air is drawn through the charge to maintain combustion of the sulphide constituent thereof, and the resulting gases containing both molsture andSO are drawn 011' by suitable draft producing means.

In the electrical precipitation of sus nded gases thus' obtaine difiiculties have arisen in obtaining efiicient cleaning and satisfactory 0 eration, but it has been found that these di iculties'may be materially decreased by increasing the concentration of S0 and moisture in the ases. In order to remedy these difiiculties t erefore, this invention provides for him g of gases in such way that the gases drawn 01f from the first zone'of the combustion region are not directly subjected to electrical precipitation but .are first utilized to supply a part, at least, of the air required for combustion in the subsequent zone, thus decreasing the total amount r-ofair'supplied and increasing the S0 and moisture gases leaving said subsequent zone.

It may be pointed out that the s arising from the first zone are natur somewhat richer in S0 and moisture, w arising from the subsequent zone are relaso tively lean, and the circulation of the gas in content of the I e the gaseszontal extent of the suction box the manner above described causes a considerable enrichment of these latter gases. The gases drawn 011' from the subsequent zone are then subjected to electrical precipitation .for removal of suspended material therefrom,

name or stir-rains om with-materially better results than heretofore have been obtained. Another advantage of this method is that the precipitator maybe of smaller size than in previous practice due to the decrease in total gas volume re sulting from re-utilization of part of the air supply.

The accompanying drawings illustrate an apparatus of the above type and the manner of applying my invention thereto and referring to these drawings:

Fig. 1 is a semi-diagrammatic side elevation of such apparatus and of the means for handling the gases and delivering the same to an electrical precipitator.

Fig. 2 is a transverse section on line 2-2 in Fig. 1. 4 v

The heat treating apparatus shown in the drawings represents a Dwight-Lloyd straight line machine, whose construction is well known, and a detailed description of the may be said that such apparatus comprises essentially a succession of ore carr elements commonly known as pallets, indicated at 1, having wheels at their ends a pair of endless tracks so as to form in offeet an endless conveyor. These pallets are caused to move around on these tracks by means of sprockets 2 adjacent the feed end of the'ma'chine, the direction of travel thereof being as indicated by the arrows in 1. The charge of ore or other material to be treated is delivered upon the Pallets as they pass successively beneath a eed hopper 3, and the combustion of the sulphide constituent is initiated by a suitable igniter 4.

The pallets are provided in the usual manner with that air the charge into suitable suction boxes extending beneath the pallets. In the present instance I have shown two such indicated at 5 and 6' respectively, the hori- 5 correspondtraveling upo1 1 p'ervious or grate-like bottoms so i may be drawn downwardly through 9'6 suction boxes least, to supply some additional air to the air box 10 and I have, therefore, shown such an box as provided with a partition 11 and with an air supply pipe 12-opening into said air box ahead of said partition and pro 'ded with a regulating damper 13, while the flue 9 opens into said air box beyond the partition 11. The gases are drawn from the suction box 6 through flue l by means of a fan or blower, l5 whence they may be delivered through flue 16 to a suitable electrical precipitatinzg apparatus indicated diagrammatically at l f a In the operation of this apparatus the ore charge is supplied onto the pallets and ignited in the usual manner and is caused to travel successively over the suction boxes 5 and 6, the treated ore being discharged from the pallets at the other end of the machine in the usual manner. In passing over the suction case when the gases are merely withdrawn in the usual manner from the suction boxes and the entire'body of such gases mixed and delivered directly to an electrical precipitator.

I claim:

A process for treatment of gases arising from a traveling charge operation for heat treatment of sulphide ores and the like, comprising drawing air through the first-zone of the combustion region, utilizing the gases from this region and relatively rich in S0 and moisture to furnish part, at least, of the air supply for combustion in a subsequent zone, so as to cause the gases leaving said subsequent zone to be-sufiiciently rich in S0 to permit eificient electrical precipitation of suspended material therefrom, separately removing the gases from this subsequent zone and subjecting such gases to an electrical precipitating operation.

In testimony whereof I have hereunto subscribed my name this 6th day of December,

HANS EENGKE.

box 5 air is drawn downwardly through the charge to support combustion of the sulphur content thereof. The gases entering said suction box, therefore, contain not only a considerable proportion oi SO but also a relatively high moisture content due to evaporation of moisture from the charge b the heat produced from such combustion. ese relatively rich ases are then circulated by fan 8 through ues 7 and 9 into the air box 10. Any desired proportion of air may also be drawn into said air box through pipe 12, the proportion of this air to the gases elivered through flue 9 depending upon the adjustment of damper 13. It will, of course be'understood that while the gases deliver 9 are relatively rich in S0: and moisturethey still consist largel of air and are, therefore, able to support er combustion and effect further removal of sulphur and moisture from the ore. The gases enterthe suction box 6 are therefore much ric er in S0 and moisture than would be the case if only pure air were drawn through this part of the charge. These ases are then delivered through flues 14 and 16 by means of fan 15 to the electrical precipitate! at 17 where the suspended material or dust 1s lar ely precipitated therefrom, and I have foun that the enrichment of the gases in the manner above described serves to permit much more efiicient and satisfactory operation of the electrical precipitator than 12 the 

